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No. 620,942. -Patented Mar. l4, I899.

L. LIAIS. I

APPARATUS FOR STAMPING METALS.

(Application filed Apr. 1'1, 1898.)

(No Model.)

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UNITED STATES PATE T ()FFIQE.

LUOIEN LIAIS, OF PARIS, FRANCE.

APPARATUS FOR STAMPING METALS.

SPECIFICATION forming part of Letters Patent No. 620,942, dated March 14, 18199. Application filed April 14, 1898. Serial No- 677,538. (No model.)

To all whom it may concern.-

Be it known that I, LUoIEN LIAIS, a citizen of the Republic of France, residing in Paris, France, have invented certain new and useful Improvements in Machines for Stamping Metals, of which the following is a specification.

This invention relates to the class of pressesor dies for stamping up hollow articles from sheet metals while cold, and particularly from tin-plate and the more refractory sheet met- In the machines heretofore commonly employed for this purpose there is a female or ring die, a male die or plunger, and a movable pressure-block to press upon and clamp the margin of the sheet-metal blank down firmly while the plunger is operating, and

thus prevent the crimping of the blank. This machine as constructed and operated has certain disadvantages, which will be hereinafter indicated; and my invention has for its object a construction of the machine which will overcome these disadvantages.

In the accompanying drawings, which serve to illustrate the ordinary construction and operation, as well as the construction embodying the present invention, Figures 1, 2, and 3 are illustrative and somewhat diagrammatic views which will be hereinafter explained. Figs. 4 and 5 are respectively side and front elevations of a machine embodying my invention, Fig. 4 being a View as seen from the left in Fig. 5. Fig. 6 is an enlarged detail View of the means for gradually elevating the pressure-block, and Fig. 7 is an enlarged detail View of the cushion device for the pressure-block.

Fig. 1 illustrates the means and operation now commonly employed in stamping sheet metals, A representing the female or ring die, B the pressure-block, and O the male die or plunger. The block B in the operation is kept pressed down firmly upon the margin of the sheet-metal blank which is being operated on. This mechanism and mode of operation has the disadvantage that it does not provide for the drawing or swaging of the metal, but maintains the metal under the block B of the uniform thickness of the blank and so is liable to cause rupture of the sheet operated on, and it has the further disadvantage that there is produced at the margin of the opening in the ring-die A, at f in Fig. l; a horizontal tangential strain, which renders the operation of stamping very difficult in practice and is productive of considerable waste. In order to overcome these objections and prevent the rupture of the metal at the point f by doing away with the main portion of the tangential strain at this point, I so construct the machine that the pressure-block B rises gradually as the plunger 0 descends and forces the blank down through the ringdie A, and said block is also caused to rise in exact proportion to the descent of the plunger. By this operation the metal of the blank is so caused to flow that it increases the thickness of the blank from center to periphery, and if the gradual rise of the block is proportioned to the normal thickness of the metal blank the latter will remain quite smooth and without crimps or wrinkles.

The article thus producedwould present the appearance seen in Fig. 3--that is, its thickness wouldincrease from the bottom to its upper edge or nargin if means were not provided for drawing down the thickened metal again to a uniform gage between the lateral surface of the plunger 0 and the vertical wall of the ring-die A, and to this end the margin f of the aperture in the ring-die is carefully rounded so as to avoid a sharp bend in the metal of the blank, and the opening in the ring-die has given to it a diameter equal to the diameter of the plunger 0, plus twice the thickness it is desired that the finished article shall have. At the point where the curve at f merges into the vertical wall of the aperture in the ringdie A the metal is drawn down to the desired thickness with ease and without danger of rupture or lamination.

To give the proper motion to the pressureblock B in a machine of the kind commonly em ployed,the construction illustrated in Figs. 4, 5, 6, and 7 may be employed. This construction I will now describe.

The crank-shaft a of the machine has at one end a crank c, on the pin of which is a runner or block D, engaging a cross groove or way gin a slide 0, to which a vertical movement is thus imparted. The slide 0 is coupled at m by links 25 to two crank-arms t, fixed, respectively, to rock-shafts o in the frame, and on said shafts are fixed arms 00,

which are coupled by links ac to the screwstems of the pressure-block B. By the above mechanism the block B will have imparted to it a vertical up-and-down movement, with a period of rest at each end of its travel. In order, however, to impart to the said block the gradual rising movement at the period when it would normally be at rest and pressing on the blank the construction is employed which will now be described with especial reference to Fig. 6. This view shows the inner face of the part G, with the cross groove or wave g and the block D therein. The upper wall 1; of the groove g, as shown in this view, slopes from y to y, the vertical rise of the incline (indicated at z in Fig. 6) being calculated and made proportionate to the extent of the gradual rise of the pressure-block desired. In the operation the block D, acting upon the upper surface 4; of the way g, will force the pressure-block 1-3 down upon the blank and press the latter firmly upon the upper surface of the ring-die A; but as the block D moves along the said surface 1: the block B will be allowed to gradually rise, owing to the inclination of said surface acting to relieve the pressure on the block 13. This easing of the pressure on said block continues until the block D comes into bearing on the lower surface of the way g, when the block B will be lifted fully.

To reduce the wear on the machine due to the sudden impact of the parts a cushioning device is introduced between the upper face of the block B and the screw-stems by which it is carried. This construction is illustrated in the detail view, Fig. 7. Under the upper clamping-nut i on the screw-stem is a springcushion 7t, composed of two cup-shaped disks of thin spring metal placed face to face. This cushion enables materials variable as to thickness to pass readily.

The size and proportions of the dies may of course be varied at will.

I have stated above that by the slight rise of the block 13 during the operation of the plunger-die the metal is so caused to flow that the thickness of the part under said block is permitted to increase. I will say, further, that in practice with the ordinary stamping-machines, where the blank was clamped tightly by the pressure-block during the stamping operation, many blanks would be so overstrained or actually ruptured as to cause an undue proportion of waste, and in some cases the tendency of the metal to flow and thicken under the pressure-block has tilted said block, and thus injured the machine. I believed that this was due to the fact that the flow of the molecules of the metal in the process of drawing was checked and that the difficulty could be obviated by permitting such flow and a consequent thickening of the metal at the upper margin of the blank under the.

pressureblock. This operation as carried out in the apparatus or machine described I find overcomes the objections stated by reducing the waste to a minimum and increasing the durability of the machine by relieving it from undue strain.

Having thus described my invention, I claim- 1. A machine for stamping sheet metals, comprising asits essentials a reciprocating plunger, a ring-die through which said plunger plays, a reciprocating pressure -block adapted to bear on the margin of the blank operated on, and means for permitting said pressure-block to rise gradually and progressively during the descent of the plunger and i in direct proportion to said descent, whereby the metal of the blank between the upper surface of the ring-die and the pressure-block is permitted to increase in thickness by the flow of the metal, substantially as and for the purpose set forth.

2. A machine for stamping sheet metals, comprising a reciprocating plunger, a female or ring die, the diameter of which is equal to that of the plunger, plus twice the thickness of the article to be produced, and which has a rounded, easing margin f, a reciprocating pressure-block adapted to bear, when down, on the margin of the blank being operated on, and means for permitting the depressed block to rise gradually and progressively to a slight extent during the descent of the plunger, whereby the metal of the blank is permitted to increase gradually in thickness under the pressure-block by the flow of the metal, and whereby the said thickened metal is continuously drawn down again to a uniform thickness, substantially as set forth.

3. A machine for stamping sheet metals, comprising a ring-die, a reciprocating plunger playing through said die, a pressure-block B, means for imparting the regular up-anddown movement to said pressure-block, and special means, substantially as described, for gradually and progressively easing the pressure on said block while it is in its depressed position, substantially as and for the purpose set forth.

a. In a machine for stamping metals, the combination with the ring-die A, the reciprocating plunger 0, and the pressure-block B, of the means for imparting a regular up-anddown motion to the said pressure-block, the cross groove or way g, in which the block D plays having its upper side, 12, inclined, sub stantially as and for the purpose set forth.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

LUOIEN LIAIS. \Vitnesses:

EDWARD P. MAOLEAN, ALEXANDER MATHIEU.

IIC 

